中文摘要：

研究在短时间模拟太阳光照射或黑暗条件下,标准天然有机质Suwannee River腐殖酸将三价金离子（Au^3＋）还原成金纳米颗粒（Au NPs）的事实.研究结果表明,活泼的腐殖酸对还原金离子这一反应在水体中广泛存在,在极端缺乏光照的水体（如地下水、溶洞水等水域）中也可进行.Pony Lake富里酸和Aldrich腐殖酸的对比试验表明,不同天然有机质在缺乏光照条件下还原Au^3＋的能力有差异.

英文摘要：

In this study, we find that one standard natural organic matter （NOM） called Suwannee River humic acid （SRHA） reduces Au^3＋ to Au nanoparticles under short-time simulated sunlight irradiation or in full-course darkness. The results suggest that the reduction of metal ions by the active NOM occurs widely, even in special aquatic environments that lack sunlight exposure, such as underground and cavern water. Moreover, analogous experiments covering other two kinds of NOMs, Pony Lake fulvic acid （PLFA） and Aldrich humic acid （AHA） , demonstrate that NOMs behave differently in reduction of Au^3＋ with limited irradiation.